Hydraulic accumulators in hydraulic systems serve, among other purposes, to receive a defined volume of pressurized fluid and to deliver it back again, as needed, to the system. Especially popular are hydraulic systems with hydropneumatic accumulators exhibiting a separating element configured as a diaphragm. The diaphragm separates, in particular, a fluid chamber acting as the working chamber from a gas chamber acting as the additional working chamber. The working gas used is preferably nitrogen. The diaphragm decouples or separates the gas and fluid chambers. The fluid chamber is connected to a hydraulic circuit of the system. As the pressure increases, the hydraulic accumulator absorbs the pressure medium, causing the gas to be compressed. As the pressure decreases, the previously compressed gas expands and at the same time forces the pressure medium (hydraulic fluid) back into the hydraulic circuit.
In general, a hydraulic accumulator is formed from two housing shells abutting each other with their free opening edges and, in doing so, defining in each case a partial volume or a working chamber of the hydraulic accumulator with the interpositioning of the diaphragm. The housing shells abutting each other at their face sides are usually welded together at the pertinent butt joint by a variety of welding methods. Depending on the welding method, it cannot be ruled out, in principle, that the hot metal beads or metal particles in the interior of the hydraulic accumulator will result in the diaphragm being damaged during the welding process. Such damage can have a negative impact on the strength of the diaphragm.